Effects of Aluminum on Hydrogen Solubility and Diffusion in Deformed Fe-Mn Alloys

Figure 2

The austenitic supercell. Fe atoms are yellow, Mn atoms are purple, and blue marks Al. The four different octahedral sites we consider are highlighted by polyhedra. The hydrogen atom can be located in direct neighbourhood of 3 Fe, 2 Mn, and 1 Al atoms (“oc1”), 4 Fe and 2 Mn atoms (“oc2”), 6 Fe atoms (“oc3”), or 5 Fe and 1 Al atom (“oc4”). Not shown here are the tetrahedral sites. We note that the oc2 configuration has the same next neighbour configuration as our reference octahedral site in the system, 4 Fe and 2 Mn atoms, but differs by the substitution of one Fe by Al. The oc1 case corresponds to the substitution of one Fe atom at the reference site with an Al atom, changing the next neighbourhood configuration as 4 Fe 2 Mn 3 Fe 2 Mn 1 Al.